AGR2-Dependent Nuclear Import of RNA Polymerase II Constitutes a Specific Target of Pancreatic Ductal Adenocarcinoma in the Context of Wild-Type p53

Less is better: various means to reduce protein load in the endoplasmic reticulum

The endoplasmic reticulum (ER) is an important organelle that controls the intracellular and extracellular environments. The ER is responsible for folding almost one-third of the total protein population in the eukaryotic cell. Disruption of ER-protein folding is associated with numerous human diseases, including metabolic disorders, neurodegenerative diseases, and cancer. During ER perturbations, the cells deploy various mechanisms to increase the ER-folding capacity and reduce ER-protein load by minimizing the number of substrates entering the ER to regain homeostasis. These mechanisms include signaling pathways, degradation mechanisms, and other processes that mediate the reflux of ER content to the cytosol. In this review, we will discuss the recent discoveries of five different ER quality control mechanisms, including the unfolded protein response (UPR), ER-associated-degradation (ERAD), pre-emptive quality control, ER-phagy and ER to cytosol signaling (ERCYS). We will discuss the roles of these processes in decreasing ER-protein load and inter-mechanism crosstalk.

NDRG1 overcomes resistance to immunotherapy of pancreatic ductal adenocarcinoma through inhibiting ATG9A-dependent degradation of MHC-1

AIMS

Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease that is resistant to immune checkpoint blockade (ICB) therapies. Emerging evidence suggests that NDRG1 may be an important target for the development of new therapies for PDAC. Herein, we investigated the novel roles of NDRG1 and Combretastatin A-4 (CA-4) in the treatment of PDAC ICB resistance.

METHODS

Enrichment of MHC class I was detected by RNA sequence and verified by RT-qPCR and immunoblotting in NDRG1-knockdown human pancreatic cancer cell lines. The protein degradation mode was found by stimulation with various inhibitors, and the autophagy degradation pathway was found by immunoprecipitation and immunolocalization. The roles of NDRG1 and MHC-I in immunotherapy were investigated by orthotopic solid tumors, histology, immunohistochemistry, multiplex immunofluorescence staining and flow cytometry.

RESULTS

Here, we identified a previously undescribed role of NDRG1 in activating major histocompatibility complex class 1 (MHC-1) expression in pancreatic ductal adenocarcinoma (PDAC) cells through lysosomal-autophagy-dependent degradation. In mouse models of PDAC, either tumor cell overexpression or pharmacologic activation of NDRG1 leads to MHC-1 upregulation in tumor cells, which in turn promotes the infiltration and activity of CD8 + T cells, enhances anti-tumor immunity, and overcomes resistance to ICB therapy. Moreover, combination therapy of CA-4 and ICB overcomes the drug resistance of pancreatic cancer to ICB therapy. In PDAC patients, NDRG1 expression correlates with high MHC-1 expression and better survival.

CONCLUSION

Our results reveal NDRG1 in PDAC cancer cells as a tumor suppressor and suggest that pharmaceutically targeting NDRG1 is a promising way to overcome pancreatic cancer resistance to immunotherapy and provides a potential therapeutic strategy for the treatment of pancreatic cancer patients.

Cell of Origin of Pancreatic cancer: Novel Findings and Current Understanding

ABSTRACT

Pancreatic ductal adenocarcinoma (PDAC) stands as one of the most lethal diseases globally, boasting a grim 5-year survival prognosis. The origin cell and the molecular signaling pathways that drive PDAC progression are not entirely understood. This review comprehensively outlines the categorization of PDAC and its precursor lesions, expounds on the creation and utility of genetically engineered mouse models used in PDAC research, compiles a roster of commonly used markers for pancreatic progenitors, duct cells, and acinar cells, and briefly addresses the mechanisms involved in the progression of PDAC. We acknowledge the value of precise markers and suitable tracing tools to discern the cell of origin, as it can facilitate the creation of more effective models for PDAC exploration. These conclusions shed light on our existing understanding of foundational genetically engineered mouse models and focus on the origin and development of PDAC.

Pancreatic ductal adenocarcinoma with acinar-to-ductal metaplasia-like cancer cells shows increased cellular proliferation

BACKGROUND/OBJECTIVES

Acinar-to-ductal metaplasia (ADM) has been shown to contribute to the development of pancreatic ductal adenocarcinoma (PDAC) in genetically engineered mouse models, but little is known about whether acinar cell plasticity contributes to carcinogenesis in human PDAC. We aimed to assess whether cancer cells that stain positive for amylase and CK19 (ADM-like cancer cells) are present in human resected PDAC and to investigate their role in tumor progression.

METHODS

We immunohistochemically investigated the presence of ADM-like cancer cells, and compared the clinical and histological parameters of PDAC patients with and without ADM-like cancer cells.

RESULTS

ADM-like cancer cells were detected in 16 of 60 (26.7%) PDAC specimens. Positive staining for anterior gradient protein 2 (AGR2) was observed in 14 of 16 (87.5%) PDAC specimens with ADM-like cancer cells. On the other hand, the intensity of AGR2 expression (negative, low/moderate or high) was lower in PDAC with ADM-like cancer cells (9/7) than in PDAC without these cells (11/33) (P = 0.032). The presence of ADM-like cancer cells was significantly correlated with increased cell proliferation (P = 0.012) and tended to be associated with MUC1 expression (P = 0.067).

CONCLUSIONS

These results indicated that acinar cells may act as the origin of human PDAC, and that their presence may be useful for the stratification of human PDAC to predict prognosis.

Integrative multi-omics and drug-response characterization of patient-derived prostate cancer primary cells

Prostate cancer (PCa) is the second most prevalent malignancy in males across the world. A greater knowledge of the relationship between protein abundance and drug responses would benefit precision treatment for PCa. Herein, we establish 35 Chinese PCa primary cell models to capture specific characteristics among PCa patients, including gene mutations, mRNA/protein/surface protein distributions, and pharmaceutical responses. The multi-omics analyses identify Anterior Gradient 2 (AGR2) as a pre-operative prognostic biomarker in PCa. Through the drug library screening, we describe crizotinib as a selective compound for malignant PCa primary cells. We further perform the pharmacoproteome analysis and identify 14,372 significant protein-drug correlations. Surprisingly, the diminished AGR2 enhances the inhibition activity of crizotinib via ALK/c-MET-AKT axis activation which is validated by PC3 and xenograft model. Our integrated multi-omics approach yields a comprehensive understanding of PCa biomarkers and pharmacological responses, allowing for more precise diagnosis and therapies.

AGR2: a secreted protein worthy of attention in diagnosis and treatment of breast cancer

AGR2 is a secreted protein widely existing in breast. In precancerous lesions, primary tumors and metastatic tumors, the expression of AGR2 is increased, which has aroused our interest. This review introduces the gene and protein structure of AGR2. Its endoplasmic reticulum retention sequence, protein disulfide isomerase active site and multiple protein binding sequences endow AGR2 with diverse functions inside and outside breast cancer cells. This review also enumerates the role of AGR2 in the progress and prognosis of breast cancer, and emphasizes that AGR2 can be a promising biomarker and a target for immunotherapy of breast cancer, providing new ideas for early diagnosis and treatment of breast cancer.

The anterior gradient homologue 2 (AGR2) co-localises with the glucose-regulated protein 78 (GRP78) in cancer stem cells, and is critical for the survival and drug resistance of recurrent glioblastoma: in situ and in vitro analyses

BACKGROUND

Glioblastomas (GBs) are characterised as one of the most aggressive primary central nervous system tumours (CNSTs). Single-cell sequencing analysis identified the presence of a highly heterogeneous population of cancer stem cells (CSCs). The proteins anterior gradient homologue 2 (AGR2) and glucose-regulated protein 78 (GRP78) are known to play critical roles in regulating unfolded protein response (UPR) machinery. The UPR machinery influences cell survival, migration, invasion and drug resistance. Hence, we investigated the role of AGR2 in drug-resistant recurrent glioblastoma cells.

METHODS

Immunofluorescence, biological assessments and whole exome sequencing analyses were completed under in situ and in vitro conditions. Cells were treated with CNSTs clinical/preclinical drugs taxol, cisplatin, irinotecan, MCK8866, etoposide, and temozolomide, then resistant cells were analysed for the expression of AGR2. AGR2 was repressed using single and double siRNA transfections and combined with either temozolomide or irinotecan.

RESULTS

Genomic and biological characterisations of the AGR2-expressed Jed66_GB and Jed41_GB recurrent glioblastoma tissues and cell lines showed features consistent with glioblastoma. Immunofluorescence data indicated that AGR2 co-localised with the UPR marker GRP78 in both the tissue and their corresponding primary cell lines. AGR2 and GRP78 were highly expressed in glioblastoma CSCs. Following treatment with the aforementioned drugs, all drug-surviving cells showed high expression of AGR2. Prolonged siRNA repression of a particular region in AGR2 exon 2 reduced AGR2 protein expression and led to lower cell densities in both cell lines. Co-treatments using AGR2 exon 2B siRNA in conjunction with temozolomide or irinotecan had partially synergistic effects. The slight reduction of AGR2 expression increased nuclear Caspase-3 activation in both cell lines and caused multinucleation in the Jed66_GB cell line.

CONCLUSIONS

AGR2 is highly expressed in UPR-active CSCs and drug-resistant GB cells, and its repression leads to apoptosis, via multiple pathways.

Biomarker discovery for practice of precision medicine in hypopharyngeal cancer: a theranostic study on response prediction of the key therapeutic agents

BACKGROUND

Hypopharyngeal cancer is a relatively rare malignancy with poor prognosis. Current chemotherapeutic algorithm is still far from personalized medicine, and the identification of the truly active therapeutic biomarkers and/or targets is eagerly awaited.

METHODS

Venturing to focus on the conventional key chemotherapeutic drugs, we identified the most correlative genes (and/or proteins) with cellular sensitivity to docetaxel (TXT), cisplatin (CDDP) and 5-fluorouracil (5-FU) in the expression levels, through 3 steps approach: genome-wide screening, confirmation study on the quantified expression levels, and knock-down and transfection analyses of the candidates. The probable action pathways of selected genes were examined by Ingenuity Pathway Analysis using a large-scale database, The Cancer Genome Atlas.

RESULTS

The first genome-wide screening study derived 16 highly correlative genes with cellular drug sensitivity in 15 cell lines (|R| > 0.8, P < 0.01 for CDDP and 5-FU; |R| > 0.5, P < 0.05 for TXT). Among 10 genes the observed correlations were confirmed in the quantified gene expression levels, and finally knock-down and transfection analyses provided 4 molecules as the most potent predictive markers-AGR2 (anterior gradient 2 homolog gene), and PDE4D (phosphodiesterase 4D, cAMP-specific gene) for TXT; NINJ2 (nerve Injury-induced protein 2); CDC25B (cell division cycle 25 homolog B gene) for 5-FU- in both gene and protein expression levels. Overexpression of AGR2, PDE4D signified worse response to TXT, and the repressed expression sensitized TXT activity. Contrary to the findings, in the other 2 molecules, NINJ2 and CDC25, there observed opposite relationship to cellular drug response to the relevant drugs. IPA raised the potential that each selected molecule functionally interacts with main action pathway (and/or targets) of the relevant drug such as tubulin β chain genes for TXT, DNA replication pathway for CDDP, and DNA synthesis pathway and thymidylate synthetase gene for 5-FU.

CONCLUSION

We newly propose 4 molecules -AGR2, PDE4D,NINJ2 and CDC25B) as the powerful exploratory markers for prediction of cellular response to 3 key chemotherapeutic drugs in hypopharyngeal cancers and also suggest their potentials to be the therapeutic targets, which could contribute to the development of precision medicine of the essential chemotherapy in hypopharyngeal patients. (339 words).

Nuclear GSK-3β and Oncogenic KRas Lead to the Retention of Pancreatic Ductal Progenitor Cells Phenotypically Similar to Those Seen in IPMN

Glycogen synthase kinase-3β (GSK-3β) is a downstream target of oncogenic KRas and can accumulate in the nucleus in pancreatic ductal adenocarcinoma (PDA). To determine the interplay between oncogenic KRas and nuclear GSK-3β in PDA development, we generated Lox-STOP-Lox (LSL) nuclear-targeted GSK-3β animals and crossed them with LSL-KRas^G12D mice under the control of the Pdx1-cre transgene—referred to as KNGC. Interestingly, 4-week-old KNGC animals show a profound loss of acinar cells, the expansion of ductal cells, and the rapid development of cystic-like lesions reminiscent of intraductal papillary mucinous neoplasm (IPMN). RNA-sequencing identified the expression of several ductal cell lineage genes including AQP5. Significantly, the Aqp5⁺ ductal cell pool was proliferative, phenotypically distinct from quiescent pancreatic ductal cells, and deletion of AQP5 limited expansion of the ductal pool. Aqp5 is also highly expressed in human IPMN along with GSK-3β highlighting the putative role of Aqp5⁺ ductal cells in human preneoplastic lesion development. Altogether, these data identify nGSK-3β and KRas^G12D as an important signaling node promoting the retention of pancreatic ductal progenitor cells, which could be used to further characterize pancreatic ductal development as well as lineage biomarkers related to IPMN and PDA.

Disruption of pancreatic stellate cell myofibroblast phenotype promotes pancreatic tumor invasion

In pancreatic ductal adenocarcinoma (PDAC), differentiation of pancreatic stellate cells (PSCs) into myofibroblast-like cancer-associated fibroblasts (CAFs) can both promote and suppress tumor progression. Here, we show that the Rho effector protein kinase N2 (PKN2) is critical for PSC myofibroblast differentiation. Loss of PKN2 is associated with reduced PSC proliferation, contractility, and alpha-smooth muscle actin (α-SMA) stress fibers. In spheroid co-cultures with PDAC cells, loss of PKN2 prevents PSC invasion but, counter-intuitively, promotes invasive cancer cell outgrowth. PKN2 deletion induces a myofibroblast to inflammatory CAF switch in the PSC matrisome signature both in vitro and in vivo. Further, deletion of PKN2 in the pancreatic stroma induces more locally invasive, orthotopic pancreatic tumors. Finally, we demonstrate that a PKN2KO matrisome signature predicts poor outcome in pancreatic and other solid human cancers. Our data indicate that suppressing PSC myofibroblast function can limit important stromal tumor-suppressive mechanisms, while promoting a switch to a cancer-supporting CAF phenotype.